(Z)-11-Eicosenyl acetate, an aggregation pheromone inDrosophila malerkotliana

(Z)-11-Eicosenyl acetate (Z11-20:Ac) was identified as the aggregation pheromone inDrosophila malerkotliana. The pheromone (200-300 ng/fly) was isolated from hexane extracts of the ejaculatory bulb of sexually mature male flies. Males released very little, if any,Z11-20:Ac to the food at any time. During mating there was a transfer of ca. 100 ng ofZ11-20:Ac to the female's reproductive tract. The mated female fly transferred theZ11-20:Ac to the surrounding surfaces in just a few hours after mating. In bioassay in a wind-tunnel olfactometer,Z11-20:Ac was not attractive alone, but was synergistic with fermenting food or with acetone. AlthoughD. malerkotliana has no (Z)-11-octadecenyl acetate (Z11-18:Ac), it was as attracted toZ11-18:Ac as to an equal quantity ofZ11-20:Ac.D. melanogaster andD. simulans, however, responded to theZ11-18: Ac that they produced and did not respond toZ11-20:Ac.